For optimal performance, a directional antenna such as a reflector antenna must be closely aligned with a target signal source. Alignment of a reflector antenna is typically performed via an adjustable antenna mount that, with respect to a fixed mounting point, is adjustable in azimuth and elevation to orient the antenna towards the target.
Because the entire antenna assembly is adjusted, the adjustable antenna mount must be designed to support the entire antenna mass and also withstand any expected environmental factors such as wind shear and or ice loading. Adjustable antenna mounts that are both strong and easily adjustable with precision significantly increase the cost of the resulting antenna.
High resolution azimuth adjustment capability is increasingly important for multiple feed reflector antennas used with satellites positioned in equatorial orbit. Where multiple feeds are applied to a single reflector to simultaneously receive closely spaced beams from different satellites, alignment is critical to achieve acceptable signal performance with respect to each of the satellites. Although equatorial orbits are generally constant by definition, in reality there is a certain range of azimuth “wobble” to an equatorial orbit that determines the precise position of the satellite at any given instant. When multiple satellites are targeted using multiple feeds of a common reflector the “wobble” position of each satellite may at one extreme or the other unacceptably degrade performance of the other signals as they move through their own ranges of positional “wobble”. High resolution adjustment capability may also be used for a single feed reflector and or terrestrial applications where precision accuracy is required.
To avoid configuring a reflector antenna for a primary satellite alignment other than the middle of a known wobble range an installation technician first aligns the antenna for maximum signal strength with respect to the primary satellite. Then, by contacting a satellite ground control resource the installation technician can obtain a desired azimuth offset representing the present distance of the primary satellite from the center of its wobble range. These adjustments are extremely small, creating a need for azimuth adjustments that are easy to perform, accurately controlled, easily measurable and reliably repeatable for a given input.
The increasing competition for reflector antennas adapted for high volume consumer applications such as satellite tv and or internet communications has focused attention on cost reductions resulting from increased materials, manufacturing and service efficiencies. Further, reductions in required assembly operations and the total number of discrete parts are desired.
Therefore, it is an object of the invention to provide an apparatus that overcomes deficiencies in the prior art.